Critical hierarchical design parameters

It is from this perspective that the National Science Foundation (NSF) sponsored a workshop entitled Periodic patterns, relationships and categories of well-defined nanoscale building blocks in 2007 [136]. This seminal workshop evolved an embryonic consensus that subsequently led to a proposed concept for defining and unifying nanoscience based on the integration of traditional chemistiy first principles with certain critical hierarchical design parameters (CHDPs) [137,138]. These CHDPs include size, shape, surface chemistiy, flexibOity/rigidity, composition, and architecture and appear to be conserved and transferred as a function of complexity (illustrated in Fig. 14). 

Fig. 14 Structural control of critical hierarchical design parameters (CHDPs), namely, size, shape, surface chemistry, flexibility/rigidity, composition, and architecture, required for bottom-up synthesis of higher nanostructural complexity manifesting atom mimicry...

Fig. 15 Front cover of Angew Chem Int Ed Engl (1990), 29 138-175 first describing structural control of critical hierarchical design parameters (CHOP) from atoms to macroscopic matter observed during the divergent syntheses of all dendrimers [9]. Copyright Wiley-VCH Verlag GmbH Co. KGaA. Reproduced with permission...

Essentially, all other proposed hard-soft nano-element categories (Fig. 18) evolve from aufbau strategies that allow the control and conservation of critical hierarchical design parameters (CHDPs) from the atomic to the nanoscale level (i.e., CADP —> CMDP —> CNDP). Nature has already evolved very exquisite aufbau strategies for synthesizing other important soft matter nano-element categories such as proteins [S-4], viral capsids [S-5], and DNA/RNA [S-6]. 

The biotic molecular evolution was defined by the respective CADPs of the combined (atoms) required to produce this new molecular level order. It is now known that within this hierarchical level, new sizes, shapes, surface chemistries (functional groups/nonbonding interactions), flexibilities (conformations), and topologies (architectures) arise. These parameters may be visualized by the various shapes, valencies, and polarizabilities associated with the element carbon in its well-known sp, sp, or sp hybridized states. We define fhese unique features as critical small molecule design parameters — CSMDPs. Molecular entities in this domain are generally < 1000 atomic mass units, thus they occupy space of up to approximately 10 A (1 nm) in diameter, when normalized as spheroids. They may be thought of as subnanoscale in dimension. 

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